What is the function of the transmission oil pump?
3 Answers
The function of the transmission oil pump is to provide hydraulic pressure for operating control valves and clutches, supply a measured amount of gear oil to the transmission and differential case, and deliver transmission fluid to the cooler for circulation and heat dissipation. Below are some details about the oil pump:1. The oil pump serves as the power source for the entire hydraulic system of an automatic transmission and is typically driven directly by the engine.2. All automatic transmissions have a front pump driven by the engine, and some transmissions also feature a rear pump driven by the output shaft. Common types of oil pumps include internal gear pumps, rotor-type pumps, and vane-type pumps.3. Some transmissions have two oil pumps housed within a single assembly, separated by a partition, operating at the same speed as the engine.
The transmission oil pump is like the heart of the entire automatic transmission, as my old mechanic buddy always describes it. It continuously draws oil from the oil pan, pressurizes it, and delivers it to the torque converter and shift clutches—without it, the whole system would be paralyzed. Last time my car had severe shifting jerks, and upon inspection, it turned out to be insufficient pressure caused by a worn-out oil pump. Crucially, it also ensures the transmission oil circulates to lubricate gears and bearings while aiding in heat dissipation. Otherwise, prolonged traffic jams could cause oil temperatures to spike and damage components. It's recommended to change the oil every 40,000 kilometers—don’t wait until the pump fails to panic. Replacing a new oil pump requires dismantling the transmission, which will definitely leave your wallet significantly lighter.
Having worked in an auto repair shop for a long time, I understand the importance of the transmission oil pump all too well. It is directly driven by the engine and has two core tasks: building pressure and maintaining circulation. The pressure must be sufficient to engage and disengage the clutch plates during gear shifts; insufficient oil pressure in older vehicles can lead to gear slippage. Circulation ensures the oil flows through the cooler to dissipate heat before lubricating the gears. Common failures include gear wear or filter clogging, which manifest as delayed shifting or abnormal noises. The key to maintenance lies in regular oil changes—fewer impurities in the oil mean the pump is less likely to seize. Nowadays, some vehicles use electric oil pumps for more precise pressure control, but mechanical pumps are simpler in structure and more reliable.
